3GPP (3rd Generation Partnership Project) LTE (long term evolution) based on 3GPP TS (Technical Specification) Release 8 is a leading next-generation mobile communication standard.
As described in 3GPP TS 36.211 V8.4.0 (2008-09) “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)”, in LTE, physical channels can be divided into a PDSCH (Physical Downlink Shared Channel) and a PUSCH (Physical Uplink Shared Channel) (i.e., data channels) and a PDSCH (Physical Downlink Control Channel) and a PUCCH (Physical Uplink Control Channel) (i.e., control channels).
System information refers to essential information for communication between a terminal and a base station. In 3GPP LTE, the system information is divided into an MIB (Master Information Block) and an SIB (System Information Block). The MIB is the most essential information. The SIB is subdivided into SIB-x forms according to its importance or cycle. The MIB is transmitted through a PBCH (Physical Broadcast Channel) which is a physical channel. The SIB is common control information and is transmitted through a PDCCH differently from the MIB.
Schemes additionally being discussed in 3GPP LTE-A (Advanced) (i.e., an evolution of 3GPP LTE) include multiple carriers, a relay, MIMO (Multiple Input Multiple Output), CoMP (Coordinated Multi-Point transmission) and the like.
With the introduction of the additional schemes, additional information elements need to be included in the system information.
As the amount of the system information is increased, it is necessary to design a channel which is used to transmit the system information by taking compatibility with the existing system into account.